Application of the stator current-based MRAS speed estimator in the sensorless induction motor drive

The paper deals with the analysis of the vector controlled induction motor drive with a novel MRAS-type rotor speed estimator. The stability analysis method of this novel MRAS estimator is proposed. The influence of equivalent circuit parameter changes of the induction motor as well as coefficients of the adaptation algorithm of the MRAS scheme to the pole placement of the estimator transfer function and stability of the whole drive system is analysed and tested. The allowable range of motor parameter changes is determined, which guarantees the stable operation of the sensorless field oriented induction motor drive with this speed and flux estimator. Dynamical performances of the vector control system with the current-type MRAS estimator are tested in the laboratory set-up.